Bilberry and Diabetes

A close relative of American blueberry, bilberry grows in northern Europe, Canada, and the United States. The ripe berries are primarily used in modern herbal extracts.

Its leaves of and the dried berries have been recommended for a wide variety of conditions, including scurvy, urinary tract infections, kidney stones, and diabetes. Perhaps the most sound historical application is the use of the dried berries to treat diarrhea. Modern research was partly based on its use by British World War II pilots, who noticed that their night vision improved when they ate bilberry jam prior to night bombing raids.

Constituents

Anthocyanosides, the flavonoid complex in bilberries, speed the regeneration of rhodopsin, the purple pigment that is used by the rods in the eye for night vision. While earlier trials suggested that taking it could benefit people with night blindness, more recent trials with healthy volunteers have found no effect of it on night vision. Preliminary human trials conducted in Europe show that it may prevent cataracts, and may even help to treat people with mild retinopathies (such as macular degeneration and diabetic retinopathy). Anthocyanosides are potent antioxidants. They support normal formation of connective tissue and strengthen capillaries in the body. Anthocyanosides may also improve capillary and venous blood flow. It may also prevent blood vessel thickening due to diabetes.

It also protects cholesterol from oxidizing in test tubes. While this action is thought to help prevent atherosclerosis, no human trials have studied whether it may be useful in the regard.

The herbal extract in capsules or tablets standardized to provide 25% anthocyanosides are typically recommended at 240–600 mg per day. Herbalists have traditionally recommended taking 1–2 ml two times per day in tincture form, or 20–60 grams of the fruit daily.

Side Effects or Interactions

In recommended amounts, no side effects have been reported with extract.